Vasopressin formulations for use in treatment of hypotension

ABSTRACT

Provided herein are peptide formulations comprising polymers as stabilizing agents. The peptide formulations can be more stable for prolonged periods of time at temperatures higher than room temperature when formulated with the polymers. The polymers used in the present invention can decrease the degradation of the constituent peptides of the peptide formulations.

SEQUENCE LISTING

The instant application contains a Sequence Listing which has been submitted electronically in ASCII format and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Jan. 28, 2015, is named 47956-701.202_SL.txt and is 5,055 bytes in size.

BACKGROUND

Vasopressin is a potent endogenous hormone, responsible for maintaining plasma osmolality and volume in most mammals. Vasopressin can be used clinically in the treatment of sepsis and cardiac conditions, and in the elevation of patient's suffering from low blood pressure. Current formulations of vasopressin require refrigeration for maintenance or reconstitution of lyophilized powders due to vasopressin's poor long-term stability.

SUMMARY OF THE INVENTION

In some embodiments, the invention provides a pharmaceutical composition comprising, in a unit dosage form: a) from about 0.01 mg/mL to about 0.07 mg/mL of vasopressin, or a pharmaceutically-acceptable salt thereof; and b) a polymeric pharmaceutically-acceptable excipient in an amount that is from about 1% to about 10% by mass of the unit dosage form or the pharmaceutically-acceptable salt thereof, wherein the unit dosage form exhibits from about 5% to about 10% less degradation of the vasopressin or the pharmaceutically-acceptable salt thereof after storage for about 1 week at about 60° C. than does a corresponding unit dosage form, wherein the corresponding unit dosage form consists essentially of: A) vasopressin, or a pharmaceutically-acceptable salt thereof; and B) a buffer having acidic pH.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a chromatogram of a diluent used in vasopressin assay.

FIG. 2 is a chromatogram of a sensitivity solution used in a vasopressin assay.

FIG. 3 is a chromatogram of an impurity marker solution used in a vasopressin assay.

FIG. 4 is a zoomed-in depiction of the chromatogram in FIG. 3.

FIG. 5 is a chromatogram of a vasopressin standard solution.

FIG. 6 is a chromatogram of a sample vasopressin preparation.

FIG. 7 is a UV spectrum of a vasopressin sample.

FIG. 8 is a UV spectrum of a vasopressin standard.

FIG. 9 plots vasopressin stability across a range of pH as determined experimentally.

FIG. 10 illustrates the effects of various stabilizers on vasopressin stability.

DETAILED DESCRIPTION Vasopressin and Peptides of the Invention.

Vasopressin, a peptide hormone, acts to regulate water retention in the body and is a neurotransmitter that controls circadian rhythm, thermoregulation, and adrenocorticotrophic hormone (ACTH) release. Vasopressin is synthesized as a pro-hormone in neurosecretory cells of the hypothalamus, and is subsequently transported to the pituitary gland for storage. Vasopressin is released upon detection of hyperosmolality in the plasma, which can be due to dehydration of the body. Upon release, vasopressin increases the permeability of collecting ducts in the kidney to reduce renal excretion of water. The decrease in renal excretion of water leads to an increase in water retention of the body and an increase in blood volume. At higher concentrations, vasopressin raises blood pressure by inducing vasoconstriction.

Vasopressin acts through various receptors in the body including, for example, the V1, V2, V3, and oxytocin-type (OTR) receptors. The V1 receptors occur on vascular smooth muscle cells, and the major effect of vasopressin action on the V1 receptor is the induction of vasoconstriction via an increase of intracellular calcium. V2 receptors occur on the collecting ducts and the distal tubule of the kidney. V2 receptors play a role in detection of plasma volume and osmolality. V3 receptors occur in the pituitary gland and can cause ACTH release upon vasopressin binding. OTRs can be found on the myometrium and vascular smooth muscle. Engagement of OTRs via vasopressin leads to an increase of intracellular calcium and vasoconstriction.

Vasopressin is a nonapeptide, illustrated below (SEQ ID NO. 1):

At neutral to acidic pH, the two basic groups of vasopressin, the N-terminal cysteine, and the arginine at position eight, are protonated, and can each carry an acetate counterion. The amide groups of the N-terminal glycine, the glutamine at position four, and the asparagine at position five, are susceptible to modification when stored as clinical formulations, such as unit dosage forms. The glycine, glutamine, and asparagine residues can undergo deamidation to yield the parent carboxylic acid and several degradation products as detailed in EXAMPLE 1 and TABLE 1 below.

Deamidation is a peptide modification during which an amide group is removed from an amino acid, and can be associated with protein degradation, apoptosis, and other regulatory functions within the cell. Deamidation of asparagine and glutamine residues can occur in vitro and in vivo, and can lead to perturbation of the structure and function of the affected proteins. The susceptibility to deamidation can depend on primary sequence of the protein, three-dimensional structure of the protein, and solution properties including, for example, pH, temperature, ionic strength, and buffer ions. Deamidation can be catalyzed by acidic conditions. Under physiological conditions, deamidation of asparagine occurs via the formation of a five-membered succinimide ring intermediate by a nucleophilic attack of the nitrogen atom in the following peptide bond on the carbonyl group of the asparagine side chain. Acetylation is a peptide modification whereby an acetyl group is introduced into an amino acid, such as on the N-terminus of the peptide.

Vasopressin can also form dimers in solution and in vivo. The vasopressin dimers can occur through the formation of disulfide bridges that bind a pair of vasopressin monomers together. The dimers can form between two parallel or anti-parallel chains of vasopressin.

Vasopressin and associated degradation products or peptides are listed in TABLE 1 below. All amino acids are L-stereoisomers unless otherwise denoted.

TABLE 1 SEQ ID Name Sequence NO. Vasopressin (AVP; CYFQNCPRG-NH₂  1 arginine vasopressin) Gly9-vasopressin CYFQNCPRG  2 (Gly9-AVP) Asp5-vasopressin CYFQDCPRG-NH₂  3 (Asp5-AVP) Glu4-vasopressin CYFENCPRG-NH₂  4 (Glu4-AVP) Glu4Gly9-vasopressin CYFENCPRG  5 (Glu4Gly9-AVP) AcetylAsp5-vasopressin Ac-CYFQDCPRG-NH₂  6 (AcetylAsp5-AVP) Acetyl-vasopressin Ac-CYFQNCPRG-NH₂  7 (Acetyl-AVP) His2-vasopressin CHFQNCPRG-NH₂  8 (His2-AVP) Leu7-vasopressin CYFQNCLRG-NH₂  9 (Leu7-AVP) D-Asn-vasopressin CYFQ(D-Asn)CPRG-NH₂ 10 (DAsn-AVP) D-Cys1-vasopressin (D-Cys)YFQNCPRG-NH₂ 11 D-Tyr-vasopressin C(D-Tyr)FQNCPRG-NH₂ 12 D-Phe-vasopressin CY(D-Phe)QNCPRG-NH₂ 13 D-Gln-vasopressin CYF(D-Gln)NCPRG-NH₂ 14 D-Cys6-vasopressin CYFQN(D-cys)PRG-NH₂ 15 D-Pro-vasopressin CYFQNC(D-pro)RG-NH₂ 16 D-Arg-vasopressin CYFQNCP(D-Arg)G-NH₂ 17

Therapeutic Uses.

A formulation of vasopressin can be used to regulate plasma osmolality and volume and conditions related to the same in a subject. Vasopressin can be used to modulate blood pressure in a subject, and can be indicated in a subject who is hypotensive despite treatment with fluid and catecholamines.

Vasopressin can be used in the treatment of, for example, vasodilatory shock, post-cardiotomy shock, sepsis, septic shock, cranial diabetes insipidus, polyuria, nocturia, polydypsia, bleeding disorders, Von Willebrand disease, haemophilia, platelet disorders, cardiac arrest, liver disease, liver failure, hypovolemia, hemorrhage, oesophageal variceal haemorrhage, hypertension, pulmonary hypertension, renal disease, polycystic kidney disease, blood loss, injury, hypotension, meniere disease, uterine myomas, brain injury, mood disorder. Formulations of vasopressin can be administered to a subject undergoing, for example, surgery or hysterectomy.

Plasma osmolality is a measure of the plasma's electrolyte-water balance and can be indicative of blood volume and hydration of a subject. Normal plasma osmolality in a healthy human subject range from about 275 milliosmoles/kg to about 295 milliosmoles/kg. High plasma osmolality levels can be due to, for example, diabetes insipidus, hyperglycemia, uremia, hypernatremia, stroke, and dehydration. Low plasma osmolality can be due to, for example, vasopressin oversecretion, improper functioning of the adrenal gland, lung cancer, hyponatremia, hypothyroidism, and over-consumption of water or other fluids.

Septic shock can develop due to an extensive immune response following infection and can result in low blood pressure. Causes of sepsis can include, for example, gastrointestinal infections, pneumonia, bronchitis, lower respiratory tract infections, kidney infection, urinary tract infections, reproductive system infections, fungal infections, and viral infections. Risk factors for sepsis include, for example, age, prior illness, major surgery, long-term hospitalization, diabetes, intravenous drug use, cancer, use of steroidal medications, and long-term use of antibiotics. The symptoms of sepsis can include, for example, cool arms and legs, pale arms and legs, extreme body temperatures, chills, light-headedness, decreased urination, rapid breathing, edema, confusion, elevated heart rate, high blood sugar, metabolic acidosis, respiratory alkalosis, and low blood pressure.

Vasopressin can also be administered to regulate blood pressure in a subject. Blood pressure is the measure of force of blood pushing against blood vessel walls. Blood pressure is regulated by the nervous and endocrine systems and can be used as an indicator of a subject's health. Chronic high blood pressure is referred to as hypertension, and chronic low blood pressure is referred to as hypotension. Both hypertension and hypotension can be harmful if left untreated.

Blood pressure can vary from minute to minute and can follow the circadian rhythm with a predictable pattern over a 24-hour period. Blood pressure is recorded as a ratio of two numbers:systolic pressure (mm Hg), the numerator, is the pressure in the arteries when the heart contracts, and diastolic pressure (mm Hg), the denominator, is the pressure in the arteries between contractions of the heart. Blood pressure can be affected by, for example, age, weight, height, sex, exercise, emotional state, sleep, digestion, time of day, smoking, alcohol consumption, salt consumption, stress, genetics, use of oral contraceptives, and kidney disease.

Blood pressure for a healthy human adult between the ages of 18-65 can range from about 90/60 to about 120/80. Hypertension can be a blood pressure reading above about 120/80 and can be classified as hypertensive crisis when there is a spike in blood pressure and blood pressure readings reach about 180/110 or higher. Hypertensive crisis can be precipitated by, for example, stroke, myocardial infarction, heart failure, kidney failure, aortic rupture, drug-drug interactions, and eclampsia. Symptoms of hypertensive crisis can include, for example, shortness of breath, angina, back pain, numbness, weakness, dizziness, confusion, change in vision, nausea, and difficulty speaking.

Vasodilatory shock can be characterized by low arterial blood pressure due to decreased systemic vascular resistance. Vasodilatory shock can lead to dangerously low blood pressure levels and can be corrected via administration of catecholamines or vasopressin formulations. Vasodilatory shock can be caused by, for example, sepsis, nitrogen intoxication, carbon monoxide intoxication, hemorrhagic shock, hypovolemia, heart failure, cyanide poisoning, metformin intoxication, and mitochondrial disease.

Post-cardiotomy shock can occur as a complication of cardiac surgery and can be characterized by, for example, inability to wean from cardiopulmonary bypass, poor hemodynamics in the operating room, development of poor hemodynamics post-surgery, and hypotension.

Pharmaceutical Formulations.

Methods for the preparation of compositions comprising the compounds described herein can include formulating the compounds with one or more inert, pharmaceutically-acceptable excipients. Liquid compositions include, for example, solutions in which a compound is dissolved, emulsions comprising a compound, or a solution containing liposomes, micelles, or nanoparticles comprising a compound as disclosed herein. These compositions can also contain minor amounts of nontoxic, auxiliary substances, such as wetting or emulsifying agents, pH buffering agents, and other pharmaceutically-acceptable additives.

Non-limiting examples of dosage forms suitable for use in the disclosure include liquid, elixir, nanosuspension, aqueous or oily suspensions, drops, syrups, and any combination thereof. Non-limiting examples of pharmaceutically-acceptable excipients suitable for use in the disclosure include granulating agents, binding agents, lubricating agents, disintegrating agents, anti-adherents, anti-static agents, surfactants, anti-oxidants, coloring agents, flavouring agents, plasticizers, preservatives, suspending agents, emulsifying agents, plant cellulosic material and spheronization agents, and any combination thereof.

Vasopressin can be formulated as an aqueous formulation or a lyophilized powder, which can be diluted or reconstituted just prior to use. Upon dilution or reconstitution, the vasopressin solution can be refrigerated for long-term stability for about one day. Room temperature incubation or prolonged refrigeration can lead to the generation of degradation products of vasopressin.

In some embodiments, a pharmaceutical composition of the invention can be formulated for long-term storage of vasopressin at room temperature in the presence of a suitable pharmaceutically-acceptable excipient. The pharmaceutically-acceptable excipient can increase the half-life of vasopressin when stored at any temperature, such as room temperature. The presence of the pharmaceutical excipient can decrease the rate of decomposition of vasopressin at any temperature, such as room temperature.

In some embodiments, a vasopressin formulation of the invention comprises a pharmaceutically-acceptable excipient, and the vasopressin has a half-life that is at least about 1%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 75%, at least about 80%, at least about 85%, at least about 90%, at least about 95%, at least about 100%, at least about 150%, at least about 200%, at least about 250%, at least about 300%, at least about 350%, at least about 400%, at least about 450%, at least about 500%, at least about 600%, at least about 700%, at least about 800%, at least about 900%, or at least about 1000% greater than the half-life of vasopressin in a corresponding formulation that lacks the pharmaceutically-acceptable excipient.

In some embodiments, a vasopressin formulation of the invention has a half-life at about 0° C. that is no more than about 1%, no more than about 5%, no more than about 10%, no more than about 15%, no more than about 20%, no more than about 25%, no more than about 30%, no more than about 35%, no more than about 40%, no more than about 45%, no more than about 50%, no more than about 55%, no more than about 60%, no more than about 65%, no more than about 70%, no more than about 75%, no more than about 80%, no more than about 85%, no more than about 90%, no more than about 95%, no more than about 100%, no more than about 150%, no more than about 200%, no more than about 250%, no more than about 300%, no more than about 350%, no more than about 400%, no more than about 450%, no more than about 500%, no more than about 600%, no more than about 700%, no more than about 800%, no more than about 900%, or no more than about 1000% greater than the half-life of the formulation at another temperature, such as room temperature.

The half-life of the compounds of the invention in a formulation described herein at a specified temperature can be, for example, about 1 hour, about 2 hours, about 3 hours, about 4 hours, about 5 hours, about 6 hours, about 7 hours, about 8 hours, about 9 hours, about 10 hours, about 11 hours, about 12 hours, about 13 hours, about 14 hours, about 15 hours, about 16 hours, about 17 hours, about 18 hours, about 19 hours, about 20 hours, about 21 hours, about 22 hours, about 23 hours, about 24 hours, about 30 hours, about 36 hours, about 42 hours, about 48 hours, about 60 hours, about 3 days, about 4 days, about 5 days, about 6 days, or about one week.

In some embodiments, a vasopressin formulation of the invention comprises an excipient and the vasopressin has a level of decomposition at a specified temperature that is about 1%, about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 100%, about 150%, about 200%, about 250%, about 300%, about 350%, about 400%, about 450%, about 500%, about 600%, about 700%, about 800%, about 900%, or about 1000% less than the level of decomposition of a formulation of the invention in the absence of the excipient.

Pharmaceutical compositions of the invention can be used, stored, tested, analyzed or assayed at any suitable temperature. Non-limiting examples of temperatures include about 0° C., about 1° C., about 2° C., about 3° C., about 4° C., about 5° C., about 6° C., about 7° C., about 8° C., about 9° C., about 10° C., about 11° C., about 12° C., about 13° C., about 14° C., about 15° C., about 16° C., about 17° C., about 18° C., about 19° C., about 20° C., about 21° C., about 22° C., about 23° C., about 24° C., about 25° C., about 26° C., about 27° C., about 28° C., about 29° C., about 30° C., about 31° C., about 32° C., about 33° C., about 34° C., about 35° C., about 36° C., about 37° C., about 38° C., about 39° C., about 40° C., about 41° C., about 42° C., about 43° C., about 44° C., about 45° C., about 46° C., about 47° C., about 48° C., about 49° C., about 50° C., about 51° C., about 52° C., about 53° C., about 54° C., about 55° C., about 56° C., about 57° C., about 58° C., about 59° C., about 60° C., about 61° C., about 62° C., about 63° C., about 64° C., about 65° C., about 66° C., about 67° C., about 68° C., about 69° C., about 70° C., about 71° C., about 72° C., about 73° C., about 74° C., or about 75° C.

Pharmaceutical compositions of the invention can be used, stored, tested, analyzed or assayed at room temperature. The room temperature can be, for example, about 20.0° C., about 20.1° C., about 20.2° C., about 20.3° C., about 20.4° C., about 20.5° C., about 20.6° C., about 20.7° C., about 20.8° C., about 20.9° C., about 21.0° C., about 21.1° C., about 21.2° C., about 21.3° C., about 21.4° C., about 21.5° C., about 21.6° C., about 21.7° C., about 21.8° C., about 21.9° C., about 22.0° C., about 22.1° C., about 22.2° C., about 22.3° C., about 22.4° C., about 22.5° C., about 22.6° C., about 22.7° C., about 22.8° C., about 22.9° C., about 23.0° C., about 23.1° C., about 23.2° C., about 23.3° C., about 23.4° C., about 23.5° C., about 23.6° C., about 23.7° C., about 23.8° C., about 23.9° C., about 24.0° C., about 24.1° C., about 24.2° C., about 24.3° C., about 24.4° C., about 24.5° C., about 24.6° C., about 24.7° C., about 24.8° C., about 24.9° C., or about 25.0° C.

A pharmaceutical composition of the disclosure can be a combination of any pharmaceutical compounds described herein with other chemical components, such as carriers, stabilizers, diluents, dispersing agents, suspending agents, thickening agents, and/or excipients. The pharmaceutical composition facilitates administration of the compound to an organism. Pharmaceutical compositions can be administered in therapeutically-effective amounts, for example, intravenous, subcutaneous, intramuscular, transdermal, or parenteral administration.

Pharmaceutical preparations can be formulated for intravenous administration. The pharmaceutical compositions can be in a form suitable for parenteral injection as a sterile suspension, solution, or emulsion in oily or aqueous vehicles, and can contain formulation agents such as suspending, stabilizing, and/or dispersing agents. Pharmaceutical formulations for parenteral administration include aqueous solutions of the active compounds in water-soluble form. Suspensions of the active compounds can be prepared as oily injection suspensions. Suitable lipophilic solvents or vehicles include fatty oils such as sesame oil, or synthetic fatty acid esters, such as ethyl oleate or triglycerides, or liposomes. Aqueous injection suspensions can contain substances which increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol, or dextran. The suspension can also contain suitable stabilizers or agents which increase the solubility of the compounds to allow for the preparation of highly concentrated solutions. Alternatively, the active ingredient can be in powder form for constitution with a suitable vehicle, for example, sterile pyrogen-free water, before use.

Comparison Formulations.

A pharmaceutical composition described herein can be analyzed by comparison to a reference formulation. A reference formulation can be generated from any combination of compounds, peptides, excipients, diluents, carriers, and solvents disclosed herein. Any compound, peptide, excipient, diluent, carrier, or solvent used to generate the reference formulation can be present in any percentage, ratio, or amount, for example, those disclosed herein. The reference formulation can comprise, consist essentially of, or consist of any combination of any of the foregoing.

A non-limiting example of a comparison formulation comprises, consists essentially of, or consists of: an amount, such as about 20 Units or about 0.04 mg, of vasopressin or a pharmaceutically-acceptable salt thereof, an amount, such as about 5 mg, of chlorobutanol (for example, hydrous), an amount, such as about 0.22 mg, of acetic acid or a pharmaceutically-acceptable salt thereof or a quantity sufficient to bring pH to about 3.4 to about 3.6, and water as needed. Another non-limiting example of a comparison formulation comprises, consists essentially of, or consists of: vasopressin or a pharmaceutically-acceptable salt thereof, chlorobutanol, acetic acid, and a solvent such as water. Another non-limiting example of a comparison formulation comprises, consists essentially of, or consists of: vasopressin or a pharmaceutically-acceptable salt thereof, chlorobutanol, and a solvent such as water. Another non-limiting example of a comparison formulation comprises, consists essentially of, or consists of: vasopressin or a pharmaceutically-acceptable salt thereof, acetic acid, and a solvent such as water. Another non-limiting example of a comparison formulation comprises, consists essentially of, or consists of: vasopressin or a pharmaceutically-acceptable salt thereof and a solvent such as water. Another non-limiting example of a comparison formulation comprises, consists essentially of, or consists of: vasopressin or a pharmaceutically-acceptable salt thereof and a buffer having acidic pH, such as pH 3.5 or any buffer or pH described herein.

Dosage Amounts.

In practicing the methods of treatment or use provided herein, therapeutically-effective amounts of the compounds described herein are administered in pharmaceutical compositions to a subject having a disease or condition to be treated. A therapeutically-effective amount can vary widely depending on the severity of the disease, the age and relative health of the subject, the potency of the compounds used, and other factors. Subjects can be, for example, humans, elderly adults, adults, adolescents, pre-adolescents, children, toddlers, infants, or neonates. A subject can be a patient.

Pharmaceutical compositions of the invention can be formulated in any suitable volume. The formulation volume can be, for example, about 0.1 mL, about 0.2 mL, about 0.3 mL, about 0.4 mL, about 0.5 mL, about 0.6 mL, about 0.7 mL, about 0.8 mL, about 0.9 mL, about 1 mL, about 1.1 mL, about 1.2 mL, about 1.3 mL, about 1.4 mL, about 1.5 mL, about 1.6 mL, about 1.7 mL, about 1.8 mL, about 1.9 mL, about 2 mL, about 2.1 mL, about 2.2 mL, about 2.3 mL, about 2.4 mL, about 2.5 mL, about 2.6 mL, about 2.7 mL, about 2.8 mL, about 2.9 mL, about 3 mL, about 3.1 mL, about 3.2 mL, about 3.3 mL, about 3.4 mL, about 3.5 mL, about 3.6 mL, about 3.7 mL, about 3.8 mL, about 3.9 mL, about 4 mL, about 4.1 mL, about 4.2 mL, about 4.3 mL, about 4.4 mL, about 4.5 mL, about 4.6 mL, about 4.7 mL, about 4.8 mL, about 4.9 mL, about 5 mL, about 5.1 mL, about 5.2 mL, about 5.3 mL, about 5.4 mL, about 5.5 mL, about 5.6 mL, about 5.7 mL, about 5.8 mL, about 5.9 mL, about 6 mL, about 6.1 mL, about 6.2 mL, about 6.3 mL, about 6.4 mL, about 6.5 mL, about 6.6 mL, about 6.7 mL, about 6.8 mL, about 6.9 mL, about 7 mL, about 7.1 mL, about 7.2 mL, about 7.3 mL, about 7.4 mL, about 7.5 mL, about 7.6 mL, about 7.7 mL, about 7.8 mL, about 7.9 mL, about 8 mL, about 8.1 mL, about 8.2 mL, about 8.3 mL, about 8.4 mL, about 8.5 mL, about 8.6 mL, about 8.7 mL, about 8.8 mL, about 8.9 mL, about 9 mL, about 9.1 mL, about 9.2 mL, about 9.3 mL, about 9.4 mL, about 9.5 mL, about 9.6 mL, about 9.7 mL, about 9.8 mL, about 9.9 mL, or about 10 mL.

A therapeutically-effective amount of a compound described herein can be present in a composition at a concentration of, for example, about 0.1 units/mL, about 0.2 units/mL, about 0.3 units/mL, about 0.4 units/mL, about 0.5 units/mL, about 0.6 units/mL, about 0.7 units/mL, about 0.8 units/mL, about 0.9 units/mL, about 1 unit/mL, about 2 units/mL, about 3 units/mL, about 4 units/mL, about 5 units/mL, about 6 units/mL, about 7 units/mL, about 8 units/mL, about 9 units/mL, about 10 units/mL, about 11 units/mL, about 12 units/mL, about 13 units/mL, about 14 units/mL, about 15 units/mL, about 16 units/mL, about 17 units/mL, about 18 units/mL, about 19 units/mL, about 20 units/mL, about 21 units/mL, about 22 units/mL, about 23 units/mL, about 24 units/mL about 25 units/mL, about 30 units/mL, about 35 units/mL, about 40 units/mL, about 45 units/mL, or about 50 units/mL.

A therapeutically-effective amount of a compound described herein can be present in a composition of the invention at a mass of about, for example, about 0.01 μg, about 0.05 μg, about 0.1 μg, about 0.15 μg, about 0.2 μg, about 0.25 μg, about 0.3 μg, about 0.35 μg, about 0.4 μg, about 0.5 μg, about 0.6 μg, about 0.7 μg, about 0.8 μg, about 0.9 μg, about 1 μg, about 2 about 3 μg, about 4 μg, about 5 μg, about 10 μg, about 15 μg, about 20 μg, about 25 μg, about 30 μg, about 35 μg, about 40 μg, about 45 about 50 μg, about 60 μg, about 70 μg, about 80 μg, about 90 μg, about 100 μg, about 125 μg, about 150 μg, about 175 μg, about 200 μg, about 250 μg, about 300 μg, about 350 μg, about 400 μg, about 450 μg, about 500 μg, about 600 μg, about 700 μg, about 800 μg, about 900 μg, about 1 mg, about 2 mg, about 3 mg, about 4 mg, about 5 mg, about 6 mg, about 7 mg, about 8 mg, about 9 mg, or about 10 mg.

A therapeutically-effective amount of a compound described herein can be present in a composition of the invention at a concentration of, for example, about 0.001 mg/mL, about 0.002 mg/mL, about 0.003 mg/mL, about 0.004 mg/mL, about 0.005 mg/mL, about 0.006 mg/mL, about 0.007 mg/mL, about 0.008 mg/mL, about 0.009 mg/mL, about 0.01 mg/mL, about 0.02 mg/mL, about 0.03 mg/mL, about 0.04 mg/mL, about 0.05 mg/mL, about 0.06 mg/mL, about 0.07 mg/mL, about 0.08 mg/mL, about 0.09 mg/mL, about 0.1 mg/mL, about 0.2 mg/mL, about 0.3 mg/mL, about 0.4 mg/mL, about 0.5 mg/mL, about 0.6 mg/mL, about 0.7 mg/mL, about 0.8 mg/mL, about 0.9 mg/mL, about 1 mg/mL, about 1.5 mg/mL, about 2 mg/mL, about 2.5 mg/mL, about 3 mg/mL, about 3.5 mg/mL, about 4 mg/mL, about 4.5 mg/mL, about 5 mg/mL, about 6 mg/mL, about 7 mg/mL, about 8 mg/mL, about 9 mg/mL, or about 10 mg/mL.

A therapeutically-effective amount of a compound described herein can be present in a composition of the invention at a unit of active agent/unit of active time. Non-limiting examples of therapeutically-effective amounts can be, for example, about 0.01 units/minute, about 0.02 units/minute, about 0.03 units/minute, about 0.04 units/minute, about 0.05 units/minute, about 0.06 units/minute, about 0.07 units/minute, about 0.08 units/minute, about 0.09 units/minute or about 0.1 units/minute.

Pharmaceutical compositions of the invention can be formulated at any suitable pH. The pH can be, for example, about 2, about 2.05, about 2.1, about 2.15, about 2.2, about 2.25, about 2.3, about 2.35, about 2.4, about 2.45, about 2.5, about 2.55, about 2.6, about 2.65, about 2.7, about 2.75, about 2.8, about 2.85, about 2.9, about 2.95, about 3, about 3.05, about 3.1, about 3.15, about 3.2, about 3.25, about 3.3, about 3.35, about 3.4, about 3.45, about 3.5, about 3.55, about 3.6, about 3.65, about 3.7, about 3.75, about 3.8, about 3.85, about 3.9, about 3.95, about 4, about 4.05, about 4.1, about 4.15, about 4.2, about 4.25, about 4.3, about 4.35, about 4.4, about 4.45, about 4.5, about 4.55, about 4.6, about 4.65, about 4.7, about 4.75, about 4.8, about 4.85, about 4.9, about 4.95, or about 5 pH units.

In some embodiments, the addition of an excipient can change the viscosity of a pharmaceutical composition of the invention. In some embodiments the use of an excipient can increase or decrease the viscosity of a fluid by at least 0.001 Pascal-second (Pa·s), at least 0.001 Pa·s, at least 0.0009 Pa·s, at least 0.0008 Pa·s, at least 0.0007 Pa·s, at least 0.0006 Pa·s, at least 0.0005 Pa·s, at least 0.0004 Pa·s, at least 0.0003 Pa·s, at least 0.0002 Pa·s, at least 0.0001 Pa·s, at least 0.00005 Pa·s, or at least 0.00001 Pa·s.

In some embodiments, the addition of an excipient to a pharmaceutical composition of the invention can increase or decrease the viscosity of the composition by at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 35%, at least 40%, at least 45%, at least 50%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or at least 99%. In some embodiments, the addition of an excipient to a pharmaceutical composition of the invention can increase or decrease the viscosity of the composition by no greater than 5%, no greater than 10%, no greater than 15%, no greater than 20%, no greater than 25%, no greater than 30%, no greater than 35%, no greater than 40%, no greater than 45%, no greater than 50%, no greater than 55%, no greater than 60%, no greater than 65%, no greater than 70%, no greater than 75%, no greater than 80%, no greater than 85%, no greater than 90%, no greater than 95%, or no greater than 99%.

Any compound herein can be purified. A compound can be at least 1% pure, at least 2% pure, at least 3% pure, at least 4% pure, at least 5% pure, at least 6% pure, at least 7% pure, at least 8% pure, at least 9% pure, at least 10% pure, at least 11% pure, at least 12% pure, at least 13% pure, at least 14% pure, at least 15% pure, at least 16% pure, at least 17% pure, at least 18% pure, at least 19% pure, at least 20% pure, at least 21% pure, at least 22% pure, at least 23% pure, at least 24% pure, at least 25% pure, at least 26% pure, at least 27% pure, at least 28% pure, at least 29% pure, at least 30% pure, at least 31% pure, at least 32% pure, at least 33% pure, at least 34% pure, at least 35% pure, at least 36% pure, at least 37% pure, at least 38% pure, at least 39% pure, at least 40% pure, at least 41% pure, at least 42% pure, at least 43% pure, at least 44% pure, at least 45% pure, at least 46% pure, at least 47% pure, at least 48% pure, at least 49% pure, at least 50% pure, at least 51% pure, at least 52% pure, at least 53% pure, at least 54% pure, at least 55% pure, at least 56% pure, at least 57% pure, at least 58% pure, at least 59% pure, at least 60% pure, at least 61% pure, at least 62% pure, at least 63% pure, at least 64% pure, at least 65% pure, at least 66% pure, at least 67% pure, at least 68% pure, at least 69% pure, at least 70% pure, at least 71% pure, at least 72% pure, at least 73% pure, at least 74% pure, at least 75% pure, at least 76% pure, at least 77% pure, at least 78% pure, at least 79% pure, at least 80% pure, at least 81% pure, at least 82% pure, at least 83% pure, at least 84% pure, at least 85% pure, at least 86% pure, at least 87% pure, at least 88% pure, at least 89% pure, at least 90% pure, at least 91% pure, at least 92% pure, at least 93% pure, at least 94% pure, at least 95% pure, at least 96% pure, at least 97% pure, at least 98% pure, at least 99% pure, at least 99.1% pure, at least 99.2% pure, at least 99.3% pure, at least 99.4% pure, at least 99.5% pure, at least 99.6% pure, at least 99.7% pure, at least 99.8% pure, or at least 99.9% pure.

Compositions of the invention can be packaged as a kit. In some embodiments, a kit includes written instructions on the administration or use of the composition. The written material can be, for example, a label. The written material can suggest conditions methods of administration. The instructions provide the subject and the supervising physician with the best guidance for achieving the optimal clinical outcome from the administration of the therapy. In some embodiments, the label can be approved by a regulatory agency, for example the U.S. Food and Drug Administration (FDA), the European Medicines Agency (EMA), or other regulatory agencies.

Pharmaceutically-Acceptable Excipients.

Non-limiting examples of pharmaceutically-acceptable excipients can be found, for example, in Remington: The Science and Practice of Pharmacy, Nineteenth Ed (Easton, Pa.: Mack Publishing Company, 1995); Hoover, John E., Remington's Pharmaceutical Sciences, Mack Publishing Co., Easton, Pa. 1975; Liberman, H. A. and Lachman, L., Eds., Pharmaceutical Dosage Forms, Marcel Decker, New York, N.Y., 1980; and Pharmaceutical Dosage Forms and Drug Delivery Systems, Seventh Ed. (Lippincott Williams & Wilkins 1999), each of which is incorporated by reference in its entirety.

In some embodiments, the pharmaceutical composition provided herein comprises a sugar as an excipient. Non-limiting examples of sugars include trehalose, sucrose, glucose, lactose, galactose, glyceraldehyde, fructose, dextrose, maltose, xylose, mannose, maltodextrin, starch, cellulose, lactulose, cellobiose, mannobiose, and combinations thereof.

In some embodiments, the pharmaceutical composition provided herein comprises a buffer as an excipient. Non-limiting examples of buffers include potassium phosphate, sodium phosphate, saline sodium citrate buffer (SSC), acetate, saline, physiological saline, phosphate buffer saline (PBS), 4-2-hydroxyethyl-1-piperazineethanesulfonic acid buffer (HEPES), 3-(N-morpholino)propanesulfonic acid buffer (MOPS), and piperazine-N,N′-bis(2-ethanesulfonic acid) buffer (PIPES), or combinations thereof.

In some embodiments, a pharmaceutical composition of the invention comprises a source of divalent metal ions as an excipient. A metal can be in elemental form, a metal atom, or a metal ion. Non-limiting examples of metals include transition metals, main group metals, and metals of Group 1, Group 2, Group 3, Group 4, Group 5, Group 6, Group 7, Group 8, Group 9, Group 10, Group 11, Group 12, Group 13, Group 14, and Group 15 of the Periodic Table. Non-limiting examples of metals include lithium, sodium, potassium, cesium, magnesium, calcium, strontium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, yttrium, zirconium, niobium, molybdenum, palladium, silver, cadmium, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, cerium, and samarium.

In some embodiments, the pharmaceutical composition provided herein comprises an alcohol as an excipient. Non-limiting examples of alcohols include ethanol, propylene glycol, glycerol, polyethylene glycol, chrlorobutanol, isopropanol, xylitol, sorbitol, maltitol, erythritol, threitol, arabitol, ribitol, mannitol, galactilol, fucitol, lactitol, and combinations thereof.

Pharmaceutical preparations can be formulated with polyethylene glycol (PEG). PEGs with molecular weights ranging from about 300 g/mol to about 10,000,000 g/mol can be used. Non-limiting examples of PEGs include PEG 200, PEG 300, PEG 400, PEG 540, PEG 550, PEG 600, PEG 1000, PEG 1450, PEG 1500, PEG 2000, PEG 3000, PEG 3350, PEG 4000, PEG 4600, PEG 6000, PEG 8000, PEG 10,000, and PEG 20,000.

Further excipients that can be used in a composition of the invention include, for example, benzalkonium chloride, benzethonium chloride, benzyl alcohol, butylated hydroxyanisole, butylated hydroxytoluene, dehydroacetic acid, ethylenediamine, ethyl vanillin, glycerin, hypophosphorous acid, phenol, phenylethyl alcohol, phenylmercuric nitrate, potassium benzoate, potassium metabisulfite, potassium sorbate, sodium bisulfite, sodium metabisulfite, sorbic acid, thimerasol, acetic acid, aluminum monostearate, boric acid, calcium hydroxide, calcium stearate, calcium sulfate, calcium tetrachloride, cellulose acetate pthalate, microcrystalline celluose, chloroform, citric acid, edetic acid, and ethylcellulose.

In some embodiments, the pharmaceutical composition provided herein comprises an aprotic solvent as an excipient. Non-limiting examples of aprotic solvents include perfluorohexane, α,α,α-trifluorotoluene, pentane, hexane, cyclohexane, methylcyclohexane, decalin, dioxane, carbon tetrachloride, freon-11, benzene, toluene, carbon disulfide, diisopropyl ether, diethyl ether, t-butyl methyl ether, ethyl acetate, 1,2-dimethoxyethane, 2-methoxyethyl ether, tetrahydrofuran, methylene chloride, pyridine, 2-butanone, acetone, N-methylpyrrolidinone, nitromethane, dimethylformamide, acetonitrile, sulfolane, dimethyl sulfoxide, and propylene carbonate.

The amount of the excipient in a pharmaceutical composition of the invention can be about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.1%, about 0.2%, about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, about 1%, about 1.5%, about 2%, about 2.5%, about 3%, about 3.5%, about 4%, about 4.5%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 60%, about 70%, about 80%, about 90%, about 100%, about 200%, about 300%, about 400%, about 500%, about 600%, about 700%, about 800%, about 900%, or about 1000% by mass of the vasopressin in the pharmaceutical composition.

The amount of the excipient in a pharmaceutical composition of the invention can be about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.1%, about 0.2%, about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, about 1%, about 1.5%, about 2%, about 2.5%, about 3%, about 3.5%, about 4%, about 4.5%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55% about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, about 99%, or about 100%, mass or by volume of the unit dosage form.

The ratio of vasopressin to an excipient in a pharmaceutical composition of the invention can be about 100:about 1, about 95:about 1, about 90:about 1, about 85:about 1, about 80:about 1, about 75:about 1, about 70:about 1, about 65:about 1, about 60:about 1, about 55:about 1, about 50:about 1, about 45:about 1, about 40:about 1, about 35:about 1 about 30:about 1, about 25:about 1, about 20:about 1, about 15:about 1, about 10:about 1, about 9:about 1, about 8:about 1, about 7:about 1, about 6:about 1, about 5:about 1, about 4:about 1, about 3:about 1, about 2:about 1, about 1:about 1, about 1:about 2, about 1:about 3, about 1:about 4, about 1:about 5, about 1:about 6, about 1:about 7, about 1:about 8, about 1:about 9, or about 1:about 10.

Pharmaceutically-Acceptable Salts.

The invention provides the use of pharmaceutically-acceptable salts of any therapeutic compound described herein. Pharmaceutically-acceptable salts include, for example, acid-addition salts and base-addition salts. The acid that is added to the compound to form an acid-addition salt can be an organic acid or an inorganic acid. A base that is added to the compound to form a base-addition salt can be an organic base or an inorganic base. In some embodiments, a pharmaceutically-acceptable salt is a metal salt. In some embodiments, a pharmaceutically-acceptable salt is an ammonium salt.

Metal salts can arise from the addition of an inorganic base to a compound of the invention. The inorganic base consists of a metal cation paired with a basic counterion, such as, for example, hydroxide, carbonate, bicarbonate, or phosphate. The metal can be an alkali metal, alkaline earth metal, transition metal, or main group metal. In some embodiments, the metal is lithium, sodium, potassium, cesium, cerium, magnesium, manganese, iron, calcium, strontium, cobalt, titanium, aluminum, copper, cadmium, or zinc.

In some embodiments, a metal salt is a lithium salt, a sodium salt, a potassium salt, a cesium salt, a cerium salt, a magnesium salt, a manganese salt, an iron salt, a calcium salt, a strontium salt, a cobalt salt, a titanium salt, an aluminum salt, a copper salt, a cadmium salt, or a zinc salt.

Ammonium salts can arise from the addition of ammonia or an organic amine to a compound of the invention. In some embodiments, the organic amine is triethyl amine, diisopropyl amine, ethanol amine, diethanol amine, triethanol amine, morpholine, N-methylmorpholine, piperidine, N-methylpiperidine, N-ethylpiperidine, dibenzylamine, piperazine, pyridine, pyrrazole, pipyrrazole, imidazole, pyrazine, or pipyrazine.

In some embodiments, an ammonium salt is a triethyl amine salt, a diisopropyl amine salt, an ethanol amine salt, a diethanol amine salt, a triethanol amine salt, a morpholine salt, an N-methylmorpholine salt, a piperidine salt, an N-methylpiperidine salt, an N-ethylpiperidine salt, a dibenzylamine salt, a piperazine salt, a pyridine salt, a pyrrazole salt, a pipyrrazole salt, an imidazole salt, a pyrazine salt, or a pipyrazine salt.

Acid addition salts can arise from the addition of an acid to a compound of the invention. In some embodiments, the acid is organic. In some embodiments, the acid is inorganic. In some embodiments, the acid is hydrochloric acid, hydrobromic acid, hydroiodic acid, nitric acid, nitrous acid, sulfuric acid, sulfurous acid, a phosphoric acid, isonicotinic acid, lactic acid, salicylic acid, tartaric acid, ascorbic acid, gentisinic acid, gluconic acid, glucaronic acid, saccaric acid, formic acid, benzoic acid, glutamic acid, pantothenic acid, acetic acid, propionic acid, butyric acid, fumaric acid, succinic acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, citric acid, oxalic acid, or maleic acid.

In some embodiments, the salt is a hydrochloride salt, a hydrobromide salt, a hydroiodide salt, a nitrate salt, a nitrite salt, a sulfate salt, a sulfite salt, a phosphate salt, isonicotinate salt, a lactate salt, a salicylate salt, a tartrate salt, an ascorbate salt, a gentisinate salt, a gluconate salt, a glucaronate salt, a saccarate salt, a formate salt, a benzoate salt, a glutamate salt, a pantothenate salt, an acetate salt, a propionate salt, a butyrate salt, a fumarate salt, a succinate salt, a methanesulfonate (mesylate) salt, an ethanesulfonate salt, a benzenesulfonate salt, a p-toluenesulfonate salt, a citrate salt, an oxalate salt, or a maleate salt.

Peptide Sequence.

As used herein, the abbreviations for the L-enantiomeric and D-enantiomeric amino acids are as follows: alanine (A, Ala); arginine (R, Arg); asparagine (N, Asn); aspartic acid (D, Asp); cysteine (C, Cys); glutamic acid (E, Glu); glutamine (Q, Gln); glycine (G, Gly); histidine (H, His); isoleucine (I, Ile); leucine (L, Leu); lysine (K, Lys); methionine (M, Met); phenylalanine (F, Phe); proline (P, Pro); serine (S, Ser); threonine (T, Thr); tryptophan (W, Trp); tyrosine (Y, Tyr); valine (V, Val). In some embodiments, the amino acid is a L-enantiomer. In some embodiments, the amino acid is a D-enantiomer.

A peptide of the disclosure can have about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 81%, about 82%, about 83%, about 84%, about 85%, about 86%, about 8′7%, about 88%, about 89%, about 90%, about 91%, about 92%, about 93%, about 94%, about 95%, about 96%, about 9′7%, about 98%, about 99%, or about 100% amino acid sequence homology to SEQ ID NO. 1.

In some embodiments, a pharmaceutical composition of the invention comprises one or a plurality of peptides having about 80% to about 90% sequence homology to SEQ ID NO. 1, about 88% to about 90% sequence homology to SEQ ID NO. 1 or 88% to 90% sequence homology to SEQ ID NO. 1. In some embodiments, a pharmaceutical composition of the invention comprises vasopression and one or more of a second, third, fourth, fifth, sixth, seventh, eighth, ninth, and tenth, peptide.

The ratio of vasopressin to another peptide in a pharmaceutical composition of the invention can be, for example, about 1000:about 1, about 990:about 1, about 980:about 1, about 970:about 1, about 960:about 1, about 950:about 1, about 800:about 1, about 700:about 1, about 600:1, about 500:about 1, about 400:about 1, about 300:about 1, about 200:about 1, about 100:about 1, about 95:about 1, about 90:about 1, about 85:about 1, about 80:about 1, about 75:about 1, about 70:about 1, about 65:about 1, about 60:about 1, about 55:about 1, about 50:about 1, about 45:about 1, about 40:about 1, about 35:about 1, about 30:about 1, about 25:about 1, about 20:about 1, about 19:about 1, about 18:about 1, about 17:about 1, about 16:about 1, about 15:about 1, about 14:about 1, about 13:about 1, about 12:about 1, about 11:about 1, or about 10:about 1.

The amount of another peptide in a composition of the invention can be, for example, about 0.01%, about 0.02%, about 0.03%, about 0.04%, about 0.05%, about 0.06%, about 0.07%, about 0.08%, about 0.09%, about 0.1%, about 0.2%, about 0.3%, about 0.4%, about 0.5%, about 0.6%, about 0.7%, about 0.8%, about 0.9%, about 1%, about 1.5%, about 2%, about 2.5%, about 3%, about 3.5%, about 4%, about 4.5%, about 5%, about 5.5%, about 6%, about 6.5%, about 7%, about 7.5%, about 8%, about 8.5%, about 9%, about 9.5%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 100% by mass of vasopressin.

Non-limiting examples of methods that can be used to identify peptides of the invention include high-performance liquid chromatography (HPLC), mass spectrometry (MS), Matrix Assisted Laser Desorption Ionization Time-of-Flight (MALDI-TOF), electrospray ionization Time-of-flight (ESI-TOF), gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), and two-dimensional gel electrophoresis.

HPLC can be used to identify peptides using high pressure to separate components of a mixture through a packed column of solid adsorbent material, denoted the stationary phase. The sample components can interact differently with the column based upon the pressure applied to the column, material used in stationary phase, size of particles used in the stationary phase, the composition of the solvent used in the column, and the temperature of the column. The interaction between the sample components and the stationary phase can affect the time required for a component of the sample to move through the column. The time required for component to travel through the column from injection point to elution is known as the retention time.

Upon elution from the column, the eluted component can be detected using a UV detector attached to the column. The wavelength of light at which the component is detected, in combination with the component's retention time, can be used to identify the component. Further, the peak displayed by the detector can be used to determine the quantity of the component present in the initial sample. Wavelengths of light that can be used to detect sample components include, for example, about 200 nM, about 225 nm, about 250 nm, about 275 nm, about 300 nm, about 325 nm, about 350 nm, about 375 nm, and about 400 nm.

Mass spectrometry (MS) can also be used to identify peptides of the invention. To prepare samples for MS analysis, the samples, containing the proteins of interest, are digested by proteolytic enzymes into smaller peptides. The enzymes used for cleavage can be, for example, trypsin, chymotrypsin, glutamyl endopeptidase, Lys-C, and pepsin. The samples can be injected into a mass spectrometer. Upon injection, all or most of the peptides can be ionized and detected as ions on a spectrum according to the mass to charge ratio created upon ionization. The mass to charge ratio can then be used to determine the amino acid residues present in the sample.

The present disclosure provides several embodiments of pharmaceutical formulations that provide advantages in stability, administration, efficacy, and modulation of formulation viscosity. Any embodiments disclosed herein can be used in conjunction or individually. For example, any pharmaceutically-acceptable excipient, method, technique, solvent, compound, or peptide disclosed herein can be used together with any other pharmaceutically-acceptable excipient, method, technique, solvent, compound, or peptide disclosed herein to achieve any therapeutic result. Compounds, excipients, and other formulation components can be present at any amount, ratio, or percentage disclosed herein in any such formulation, and any such combination can be used therapeutically for any purpose described herein and to provide any viscosity described herein.

EXAMPLES Example 1: Impurities of Vasopressin as Detected by HPLC

To analyze degradation products of vasopressin that can be present in an illustrative formulation of vasopressin, gradient HPLC was performed to separate vasopressin from related peptides and formulation components. TABLE 2 below depicts the results of the experiment detailing the chemical formula, relative retention time (RRT), molar mass, and structure of vasopressin and detected impurities.

Vasopressin was detected in the eluent using UV absorbance. The concentration of vasopressin in the sample was determined by the external standard method, where the peak area of vasopressin in sample injections was compared to the peak area of vasopressin reference standards in a solution of known concentration. The concentrations of related peptide impurities in the sample were also determined using the external standard method, using the vasopressin reference standard peak area and a unit relative response factor. An impurities marker solution was used to determine the relative retention times of identified related peptides at the time of analysis.

Experimental conditions are summarized in TABLE 2 below.

TABLE 2 Column YMC-Pack ODS-AM, 3 μm, 120 Å pore, 4.6 × 100 mm Column Temperature 25° C. Flow Rate 1.0 mL/min Detector 215 nm Note: For Identification a Diode Array Detector (DAD) was used with the range of 200-400 nm. Injection Volume 100 μL Run time 55 minutes Autosampler Vials Polypropylene vials Time (min) % A % B Flow Pump (gradient) 0 90 10 1.0 40 50 50 1.0 45 50 50 1.0 46 90 10 1.0 55 90 10 1.0

The diluent used for the present experiment was 0.25% v/v Acetic Acid, which was prepared by transferring 2.5 mL of glacial acetic acid into a 1-L volumetric flask containing 500 mL of water. The solution was diluted to the desired volume with water.

Phosphate buffer at pH 3.0 was used for mobile phase A. The buffer was prepared by weighing approximately 15.6 g of sodium phosphate monobasic monohydrate into a beaker. 1000 mL of water was added, and mixed well. The pH was adjusted to 3.0 with phosphoric acid. The buffer was filtered through a 0.45 μm membrane filter under vacuum, and the volume was adjusted as necessary.

An acetonitrile:water (50:50) solution was used for mobile phase B. To prepare mobile phase B, 500 mL of acetonitrile was mixed with 500 mL of water.

The working standard solution contained approximately 20 units/mL of vasopressin. The standard solution was prepared by quantitatively transferring the entire contents of 1 vial of USP Vasopressin RS with diluent to a 50-mL volumetric flask.

The intermediate standard solution was prepared by pipetting 0.5 mL of the working standard solution into a 50-mL volumetric flask.

The sensitivity solution was prepared by pipetting 5.0 mL of the intermediate standard solution into a 50-mL volumetric flask. The solution was diluted to the volume with Diluent and mixed well.

A second working standard solution was prepared as directed under the standard preparation.

A portion of the vasopressin control sample was transferred to an HPLC vial and injected. The control was stable for 120 hours when stored in autosampler vials at ambient laboratory conditions.

To prepare the impurities marker solution, a 0.05% v/v acetic acid solution was prepared by pipetting 200.0 mL of a 0.25% v/v acetic acid solution into a 1-L volumetric flask. The solution was diluted to the desired volume with water and mixed well.

To prepare the vasopressin impurity stock solutions, the a solution of each impurity was prepared in a 25 mL volumetric flask and diluted with 0.05% v/v acetic acid to a concentration suitable for HPLC injection.

To prepare the MAA/H-IBA (Methacrylic Acid/α-Hydroxy-isobutyric acid) stock solution, a stock solution containing approximately 0.3 mg/mL H-IBA and 0.01 mg/mL in 0.05% v/v acetic acid was made in a 50 mL volumetric flask.

To prepare the chlorobutanol diluent, about one gram of hydrous chlorobutanol was added to 500 mL of water. Subsequently, 0.25 mL of acetic acid was added and the solution was stirred to dissolve the chlorobutanol.

To prepare the impurity marker solution, vasopressin powder was mixed with the impurity stock solutions prepared above.

The solutions were diluted to volume with the chlorobutanol diluent. The solutions were aliquoted into individual crimp top vials and stored at 2-8° C. At time of use, the solutions were removed from refrigeration (2-8° C.) and allowed to reach room temperature.

The vasopressin impurity marker solution was stable for at least 120 hours when stored in auto-sampler vials at ambient laboratory conditions. The solution was suitable for use as long as the chromatographic peaks could be identified based on comparison to the reference chromatogram.

To begin the analysis, the HPLC system was allowed to equilibrate for at least 30 minutes using mobile phase B, followed by time 0 min gradient conditions until a stable baseline was achieved.

The diluent was injected at the beginning of the run, and had no peaks that interfered with Vasopressin at around 18 minutes as shown in FIG. 1.

A single injection of the sensitivity solution was performed, wherein the signal-to-noise ratio of the Vasopressin was greater than or equal to ten as shown in FIG. 2.

A single injection of the impurities marker solution was then made. The labeled impurities in the reference chromatogram were identified in the chromatogram of the marker solution based on their elution order and approximate retention times shown in FIG. 3 and FIG. 4. FIG. 4 is a zoomed in chromatograph of FIG. 3 showing the peaks that eluted between 15 and 30 minutes. The nomenclature, structure, and approximate retention times for individual identified impurities are detailed in TABLE 3.

A single injection of the working standard solution was made to ensure that the tailing factor of the vasopressin peak was less than or equal to about 2.0 as shown in FIG. 5.

A total of five replicate injections of the working standard solution were made to ensure that the relative standard deviation (% RSD) of the five replicate vasopressin peak areas was not more than 2.0%.

Two replicate injections of the check standard preparation were to confirm that the check standard conformity was 99.0%-101.0%. One injection of the control sample was made to confirm that the assay of the control sample met the control limits established for the sample.

Then, one injection of the working standard solution was made.

Following the steps above done to confirm system suitability, a single injection of each sample preparation was made. The chromatograms were analyzed to determine the vasopressin and impurity peak areas. The chromatogram is depicted in FIG. 6.

The working standard solution was injected after 1 to 4 sample injections, and the bracketing standard peak areas were averaged for use in the calculations to determine peak areas of vasopressin and associated impurities.

The relative standard deviation (% RSD) of vasopressin peak areas for the six injections of working standard solution was calculated by including the initial five injections from the system suitability steps above and each of the subsequent interspersed working standard solution injections. The calculations were done to ensure that each of the % RSD were not more than 2.0%.

The retention time of the major peak in the chromatogram of the sample preparation corresponded to that of the vasopressin peak in the working standard solution injection that preceded the sample preparation injection.

The UV spectrum (200-400 nm) of the main peak in the chromatogram of the sample preparation compared to the UV spectrum of vasopressin in the working standard preparation. FIG. 7 depicts a UV spectrum of a vasopressin sample and FIG. 8 depicts a UV spectrum of vasopressin standard.

To calculate the vasopressin units/mL, the following formula was used:

${{Vasopressin}\mspace{14mu} {{units}/{mL}}} = {\frac{R_{U}}{R_{S}} \times {Conc}\mspace{14mu} {STD}}$

where:

R_(U)=Vasopressin peak area response of Sample preparation.

R_(S)=average vasopressin peak area response of bracketing standards.

Conc STD=concentration of the vasopressin standard in units/mL

To identify the impurities, the % Impurity and identity for identified impurities (TABLE 3) that are were greater than or equal to 0.10% were reported. Impurities were truncated to 3 decimal places and then rounded to 2 decimal places, unless otherwise specified.

The impurities were calculated using the formula below:

${\% \mspace{14mu} {impurity}} = {\frac{R_{I}}{R_{S}} \times \frac{{Conc}\mspace{14mu} {STD}}{20\mspace{14mu} {U/{mL}}} \times 100\%}$

where:

R₁=Peak area response for the impurity

20 U/mL=Label content of vasopressin

TABLE 3 below details the chemical formula, relative retention time (RRT in minutes), molar mass, and structure of vasopressin and detected impurities.

TABLE 3 Name Formula Appr. RRT Molar Mass (g) Vasopressin C₄₆H₆₅N₁₅O₁₂S₂ 1.00 1084.23 (Arginine Vasopressin, AVP) CYFQNCPRG-NH₂ SEQ ID NO.: 1 (disulfide bridge between cys residues) Gly9-vasopressin C₄₆H₆₄N₁₄O₁₃S₂ 1.07 1085.22 (Gly9-AVP) CYFQNCPRG SEQ ID NO.: 2 (disulfide bridge between cys residues) Asp5-vasopressin C₄₆H₆₄N₁₄O₁₃S₂ 1.09 1085.22 (Asp5-AVP) CYFQDCPRG-NH₂ SEQ ID NO.: 3 (disulfide bridge between cys residues) Glu4-vasopressin C₄₆H₆₄N₁₄O₁₃S₂ 1.12 1085.22 (Glu4-AVP) CYFENCPRG-NH₂ SEQ ID NO.: 4 (disulfide bridge between cys residues) Acetyl-vasopressin C₄₈H₆₇N₁₅O₁₃S₂ 1.45 1126.27 (Acetyl-AVP) Ac-CYFQNCPRG-NH₂ SEQ ID NO.: 7 (disulfide bridge between cys residues) D-Asn-vasopressin C₄₆H₆₅N₁₅O₁₂S₂ 0.97 1084.23 (DAsn-AVP) CYFQ(D-Asn)CPRG-NH₂ SEQ ID NO.: 10 (disulfide bridge between cys residues) Dimeric-vasopressin C₉₂H₁₃₀N₃₀O₂₄S₄ 1.22 2168.46 (Dimer-AVP) (monomers cross linked by disulfide bridges)

Example 2: Investigation of pH

To determine a possible pH for a vasopressin formulation with good shelf life, vasopressin formulations were prepared in 10 mM citrate buffer diluted in isotonic saline across a range of pH. Stability was assessed via HPLC as in EXAMPLE 1 after incubation of the formulations at 60° C. for one week. FIG. 9 illustrates the results of the experiment. The greatest level of stability was observed at pH 3.5. At pH 3.5, the percent label claim (% LC) of vasopressin was highest, and the proportion of total impurities was lowest.

Example 3: Effect of Peptide Stabilizers on Vasopressin Formulation

To observe the effect of stabilizers on the degradation of vasopressin, a series of peptide stabilizers were added to a vasopressin formulation as detailed in TABLE 4. Stability of vasopressin was assessed via HPLC after incubation of the formulations at 60° C. for one week.

TABLE 4 PEG Poloxamer n-Methylpyrrolidone Ethanol 400 Glycerol 188 HPbCD^(a) (NMP) 1% 1% 1% 1% 1% 1% 10% 10% 10% 10% 10% 10% ^(a)Hydroxypropyl beta-Cyclodextrin

FIG. 10 illustrates the stability of vasopressin in terms of % label claim at varying concentrations of stabilizer. The results indicate that the tested stabilizers provided a greater stabilizing effect at 1% concentration than at 10%. Also, in several cases the stabilization effect was about 5% to about 10% greater than that observed in the experiments of EXAMPLE 2.

Example 4: Effect of Buffer and Divalent Metals on Vasopressin Formulation

To determine whether different combinations of buffers and use of divalent metals affect vasopressin stability, vasopressin formulations with varying concentrations of citrate and acetate buffers and variable concentrations of calcium, magnesium, and zinc ions were prepared. Solutions of 0 mM, 10 mM, 20 mM, and 80 mM calcium, magnesium, and zinc were prepared and each was combined with 1 mM or 10 mM of citrate or acetate buffers to test vasopressin stability.

The tested combinations provided vasopressin stability comparable to that of a vasopressin formulation lacking buffers and divalent metals. However, that the addition of divalent metal ions was able to counteract the degradation of vasopressin caused by the use of a citrate buffer.

Example 5: Effect of Non-Aqueous Solvent Formulations on Vasopressin Stability

Several solvents were used to prepare vasopressin formulations to assess vasopressin stability. The formulations were prepared at 400 μg/mL and stability was tested via HPLC after incubation at 60° C. for one week, 40° C. for four weeks, and 25° C. for four weeks. The examined solvents included water, DMSO, propylene glycol, PEG300, NMP, glycerol, and ethanol. None of the tested solvents were able to increase the stability of vasopressin in solution in comparison to an aqueous formulation lacking a cosolvent.

Example 6: Illustrative Formulations for Assessment of Vasopressin Stability

An aqueous formulation of vasopressin is prepared using 10% trehalose, 1% sucrose, or 5% NaCl and incubated at 60° C. for one week, at which point stability of vasopressin is assessed using HPLC.

A formulation containing 50 units of vasopressin is lyophilized. The lyophilate is reconstituted with water and either 100 mg of sucrose or 100 mg of lactose, and the stability of vasopressin is tested via HPLC after incubation at 60° C. for one week.

Co-solvents are added to a vasopressin solution to assess vasopressin stability. 95% solvent/5% 20 mM acetate buffer solutions are prepared using propylene glycol, DMSO, PEG300, NMP, glycerol, and glycerol:NMP (1:1), and used to create formulations of vasopressin. The stability of vasopressin is tested after incubation at 60° C. for one week.

Amino acid and phosphate buffers are tested with vasopressin to assess vasopressin stability. Buffers of 10 mM glycine, aspartate, phosphate are prepared at pH 3.5 and 3.8 and used to create formulations of vasopressin. The stability of vasopressin is tested after incubation at 60° C. for one week.

A vasopressin formulation in 10% polyvinylpyrrolidone is prepared to assess vasopressin stability. The stability of vasopressin will be tested after incubation at 60° C. for one week.

A vasopressin formulation that contains 0.9% saline, 10 mM acetate buffer, 0.2 unit/mL API/mL in 100 mL of total volume is prepared. The pH of the solution is varied from pH 3.5-3.8 to test the stability of vasopressin.

A vasopressin formulation in about 50% to about 80% DMSO (for example, about 80%), about 20% to about 50% ethyl acetate (for example, about 20%), and about 5% to about 30% polyvinylpyrrolidone (PVP) (for example, about 10% by mass of the formulation) is prepared to assess vasopressin stability. PVP K12 and PVP K17 are each independently tested in the formulation. The stability of vasopressin is tested after incubation at 60° C. for one week.

A vasopressin formulation in about 70% to about 95% ethyl acetate, and about 5% to about 30% PVP is prepared to assess vasopressin stability. PVP K12 and PVP K17 are each independently tested in the formulation. The stability of vasopressin is tested after incubation at 60° C. for one week.

A vasopressin formulation in 90% DMSO and 10% PVP is prepared to test vasopressin stability. PVP K12 and PVP K17 are each independently tested in the formulation. The stability of vasopressin is tested after incubation at 60° C. for one week.

Example 7: Illustrative Vasopressin Formulation for Clinical Use

A formulation for vasopressin that can be used in the clinic is detailed in TABLE 5 below:

TABLE 5 Ingredient Function Amount (per mL) Vasopressin, USP Active Ingredient 20 Units (~0.04 mg) Chlorobutanol, Hydrous NF Preservative 5.0 mg Acetic Acid, NF pH Adjustment To pH 3.4-3.6 (~0.22 mg) Water for injection, USP/EP Diluent QS

Example 8: Illustrative Regimen for Therapeutic Use of a Vasopressin Formulation

Vasopressin is indicated to increase blood pressure in adults with vasodilatory shock (for example, adults who are post-cardiotomy or septic) who remain hypotensive despite fluids and catecholamines.

Preparation and Use of Vasopressin.

Vasopressin is supplied in a carton of 25 multi-dose vials each containing 1 mL vasopressin at 20 units/mL.

Vasopressin is stored between 15° C. and 25° C. (59° F. and 77° F.), and is not frozen.

Vials of vasopressin are to be discarded 48 hours after first puncture.

Vasopressin is prepared according to TABLE 6 below:

TABLE 6 Mix Fluid Restriction? Final Concentration Vasopressin Diluent No 0.1 units/mL 2.5 mL (50 units) 500 mL Yes  1 unit/mL   5 mL (100 units) 100 mL

Vasopressin is diluted in normal saline (0.9% sodium chloride) or 5% dextrose in water (D5W) prior to use to either 0.1 units/mL or 1 unit/mL for intravenous administration. Unused diluted solution is discarded after 18 hours at room temperature or after 24 hours under refrigeration.

Diluted vasopressin should be inspected for particulate matter and discoloration prior to use whenever solution and container permit.

The goal of treatment with vasopressin is optimization of perfusion to critical organs, but aggressive treatment can compromise perfusion of organs, like the gastrointestinal tract, for which function is difficult to monitor. Titration of vasopressin to the lowest dose compatible with a clinically-acceptable response is recommended.

For post-cardiotomy shock, a dose of 0.03 units/minute is used as a starting point. For septic shock, a dose of 0.01 units/minute is recommended. If the target blood pressure response is not achieved, titrate up by 0.005 units/minute at 10- to 15-minute intervals. The maximum dose for post-cardiotomy shock is 0.1 units/minute and for septic shock 0.07 units/minute. After target blood pressure has been maintained for 8 hours without the use of catecholamines, taper vasopressin by 0.005 units/minute every hour as tolerated to maintain target blood pressure.

Vasopressin is provided at 20 units per mL of diluent, which is packaged as 1 mL of vasopressin per vial, and is diluted prior to administration.

Contraindications, Adverse Reactions, and Drug-Drug Interactions.

Vasopressin is contraindicated in patients with known allergy or hypersensitivity to 8-L-arginine vasopressin or chlorobutanol. Additionally, use of vasopressin in patients with impaired cardiac response can worsen cardiac output.

Adverse reactions have been observed with the use of vasopressin, which adverse reactions include bleeding/lymphatic system disorders, specifically, hemorrhagic shock, decreased platelets, intractable bleeding; cardiac disorders, specifically, right heart failure, atrial fibrillation, bradycardia, myocardial ischemia; gastrointestinal disorders, specifically, mesenteric ischemia; hepatobiliary disorders, specifically, increased bilirubin levels; renal/urinary disorders, specifically, acute renal insufficiency; vascular disorders, specifically, distal limb ischemia; metabolic disorders, specifically, hyponatremia; and skin disorders, specifically, and ischemic lesions.

These reactions are reported voluntarily from a population of uncertain size. Thus, reliable estimation of frequency or establishment of a causal relationship to drug exposure is unlikely.

Vasopressin has been observed to interact with other drugs. For example, use of vasopressin with catecholamines is expected to result in an additive effect on mean arterial blood pressure and other hemodynamic parameters. Use of vasopressin with indomethacin can prolong the effect of vasopressin on cardiac index and systemic vascular resistance. Indomethacin more than doubles the time to offset for vasopressin's effect on peripheral vascular resistance and cardiac output in healthy subjects.

Further, use of vasopressin with ganglionic blocking agents can increase the effect of vasopressin on mean arterial blood pressure. The ganglionic blocking agent tetra-ethylammonium increases the pressor effect of vasopressin by 20% in healthy subjects.

Use of vasopressin with furosemide increases the effect of vasopressin on osmolar clearance and urine flow. Furosemide increases osmolar clearance 4-fold and urine flow 9-fold when co-administered with exogenous vasopressin in healthy subjects.

Use of vasopressin with drugs suspected of causing SIADH (Syndrome of inappropriate antidiuretic hormone secretion), for example, SSRIs, tricyclic antidepressants, haloperidol, chlorpropamide, enalapril, methyldopa, pentamidine, vincristine, cyclophosphamide, ifosfamide, and felbamate can increase the pressor effect in addition to the antidiuretic effect of vasopressin. Additionally, use of vasopressin with drugs suspected of causing diabetes insipidus for example, demeclocycline, lithium, foscarnet, and clozapine can decrease the pressor effect in addition to the antidiuretic effect of vasopressin.

Halothane, morphine, fentanyl, alfentanyl and sufentanyl do not impact exposure to endogenous vasopressin.

Use of Vasopressin in Specific Populations.

Vasopressin is a Category C drug for pregnancy.

Due to a spillover into the blood of placental vasopressinase, the clearance of exogenous and endogenous vasopressin increases gradually over the course of a pregnancy. During the first trimester of pregnancy the clearance is only slightly increased. However, by the third trimester the clearance of vasopressin is increased about 4-fold and at term up to 5-fold. Due to the increased clearance of vasopressin in the second and third trimester, the dose of vasopressin can be up-titrated to doses exceeding 0.1 units/minute in post-cardiotomy shock and 0.07 units/minute in septic shock. Vasopressin can produce tonic uterine contractions that could threaten the continuation of pregnancy. After delivery, the clearance of vasopressin returns to preconception levels.

Overdosage.

Overdosage with vasopressin can be expected to manifest as a consequence of vasoconstriction of various vascular beds, for example, the peripheral, mesenteric, and coronary vascular beds, and as hyponatremia. In addition, overdosage of vasopressin can lead less commonly to ventricular tachyarrhythmias, including Torsade de Pointes, rhabdomyolysis, and non-specific gastrointestinal symptoms. Direct effects of vasopressin overdose can resolve within minutes of withdrawal of treatment.

Pharmacology of Vasopressin.

Vasopressin is a polypeptide hormone that causes contraction of vascular and other smooth muscles and antidiuresis, which can be formulated as a sterile, aqueous solution of synthetic arginine vasopressin for intravenous administration. The 1 mL solution contains vasopressin 20 units/mL, chlorobutanol, NF 0.5% as a preservative, and water for injection, USP adjusted with acetic acid to pH 3.4-3.6.

The chemical name of vasopressin is Cyclo (1-6) L-Cysteinyl-L-Tyrosyl-L-Phenylalanyl-L-Glutaminyl-L-Asparaginyl-L-Cysteinyl-L-Prolyl-L-Arginyl-L-Glycinamide. Vasopressin is a white to off-white amorphous powder, freely soluble in water. The structural formula of vasopressin is:

One mg of vasopressin is equivalent to 530 units.

The vasoconstrictive effects of vasopressin are mediated by vascular V1 receptors. Vascular V1 receptors are directly coupled to phopholipase C, resulting in release of calcium, leading to vasoconstriction. In addition, vasopressin stimulates antidiuresis via stimulation of V2 receptors which are coupled to adenyl cyclase.

At therapeutic doses, exogenous vasopressin elicits a vasoconstrictive effect in most vascular beds including the splanchnic, renal, and cutaneous circulation. In addition, vasopressin at pressor doses triggers contractions of smooth muscles in the gastrointestinal tract mediated by muscular V1-receptors and release of prolactin and ACTH via V3 receptors. At lower concentrations typical for the antidiuretic hormone, vasopressin inhibits water diuresis via renal V2 receptors. In patients with vasodilatory shock, vasopressin in therapeutic doses increases systemic vascular resistance and mean arterial blood pressure and reduces the dose requirements for norepinephrine.

Vasopressin tends to decrease heart rate and cardiac output. The pressor effect is proportional to the infusion rate of exogenous vasopressin. Onset of the pressor effect of vasopressin is rapid, and the peak effect occurs within 15 minutes. After stopping the infusion, the pressor effect fades within 20 minutes. There is no evidence for tachyphylaxis or tolerance to the pressor effect of vasopressin in patients.

At infusion rates used in vasodilatory shock (0.01-0.1 units/minute), the clearance of vasopressin is 9 to 25 mL/min/kg in patients with vasodilatory shock. The apparent half-life of vasopressin at these levels is <10 minutes. Vasopressin is predominantly metabolized and only about 6% of the dose is excreted unchanged in urine. Animal experiments suggest that the metabolism of vasopressin is primarily by liver and kidney. Serine protease, carboxipeptidase and disulfide oxido-reductase cleave vasopressin at sites relevant for the pharmacological activity of the hormone. Thus, the generated metabolites are not expected to retain important pharmacological activity.

Carcinogenesis, Mutagenesis, Impairment of Fertility.

Vasopressin was found to be negative in the in vitro bacterial mutagenicity (Ames) test and the in vitro Chinese hamster ovary (CHO) cell chromosome aberration test. In mice, vasopressin can have an effect on function and fertilizing ability of spermatozoa.

Clinical Studies.

Increases in systolic and mean blood pressure following administration of vasopressin were observed in seven studies in septic shock and eight studies in post-cardiotomy vasodilatory shock.

Embodiments

The following non-limiting embodiments provide illustrative examples of the invention, but do not limit the scope of the invention.

In some embodiments, the invention provides a pharmaceutical composition comprising, in a unit dosage form: a) from about 0.01 mg/mL to about 0.07 mg/mL of vasopressin, or a pharmaceutically-acceptable salt thereof; and b) a polymeric pharmaceutically-acceptable excipient in an amount that is from about 1% to about 10% by mass of the unit dosage form or the pharmaceutically-acceptable salt thereof, wherein the unit dosage form exhibits from about 5% to about 10% less degradation of the vasopressin or the pharmaceutically-acceptable salt thereof after storage for about 1 week at about 60° C. than does a corresponding unit dosage form, wherein the corresponding unit dosage form consists essentially of: A) vasopressin, or a pharmaceutically-acceptable salt thereof; and B) a buffer having acidic pH. In some embodiments, the polymeric pharmaceutically-acceptable excipient comprises a polyalkylene oxide moiety. In some embodiments, the polymeric pharmaceutically-acceptable excipient is a polyethylene oxide. In some embodiments, the polymeric pharmaceutically-acceptable excipient is a poloxamer. In some embodiments, the unit dosage form has an amount of the polymeric pharmaceutically-acceptable excipient that is about 1% the amount of the vasopressin or the pharmaceutically-acceptable salt thereof. In some embodiments, the first unit dosage form exhibits about 10% less degradation of the vasopressin or the pharmaceutically-acceptable salt thereof after storage for about 1 week at about 60° C. than does the corresponding unit dosage form. In some embodiments, the unit dosage form further comprises SEQ ID NO. 2. In some embodiments, the composition further comprises SEQ ID NO. 3. In some embodiments, the composition further comprises SEQ ID NO. 4. In some embodiments, the unit dosage form is an injectable of about 1 mL volume. In some embodiments, the unit dosage form consists essentially of: a) about 0.04 mg/mL of vasopressin, or the pharmaceutically-acceptable salt thereof; b) the polymeric pharmaceutically-acceptable excipient in an amount that is from about 1% to about 10% by mass of the vasopressin or the pharmaceutically-acceptable salt thereof; and c) a plurality of peptides, wherein each of the peptides has from 88% to 90% sequence homology to the vasopressin or the pharmaceutically-acceptable salt thereof. In some embodiments, one of the plurality of peptides is SEQ ID NO.: 2. In some embodiments, one of the plurality of peptides is SEQ ID NO.:3. In some embodiments, wherein one of the plurality of peptides is SEQ ID NO.: 4. In some embodiments, the buffer has a pH of about 3.5. 

1-15. (canceled)
 16. A method for increasing blood pressure in a subject in need thereof, the method comprising a) providing a pharmaceutical composition comprising: 20 units/mL vasopressin, or a pharmaceutically acceptable salt thereof; a pharmaceutically acceptable excipient which is acetic acid, acetate, or a combination thereof; optionally chlorobutanol; and water, wherein the pharmaceutical composition is at a pH of about 3.5 to about 4.1, and the purity of vasopressin is at least 97% by HPLC; b) diluting the pharmaceutical composition with a diluent to provide a concentration from 0.1 units/mL to 1 unit/mL vasopressin, or a pharmaceutically acceptable salt thereof, wherein the diluent is about 0.9% sodium chloride or about 5% dextrose; c) intravenously administering the diluted pharmaceutical composition to the subject.
 17. The method of claim 16, wherein the purity of vasopressin in the pharmaceutical composition is at least 98% by HPLC.
 18. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 2 at an amount of about 0.1% by mass of vasopressin.
 19. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 2 at an amount of about 0.2% by mass of vasopressin.
 20. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 2 at an amount of about 0.5% by mass of vasopressin.
 21. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 2 at an amount of about 0.6% by mass of vasopressin.
 22. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 2 at an amount of about 0.7% by mass of vasopressin.
 23. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 2 at an amount of about 0.8% by mass of vasopressin.
 24. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 4 at an amount of about 0.1% by mass of vasopressin.
 25. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 4 at an amount of about 0.5% by mass of vasopressin.
 26. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 4 at an amount of about 0.6% by mass of vasopressin.
 27. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 4 at an amount of about 0.7% by mass of vasopressin.
 28. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 4 at an amount of about 0.8% by mass of vasopressin.
 29. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 4 at an amount of about 0.9% by mass of vasopressin.
 30. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 3 at an amount of less than about 0.1% by mass of vasopressin.
 31. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 3 at an amount of about 0.1% by mass of vasopressin.
 32. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 3 at an amount of about 0.2% by mass of vasopressin.
 33. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 7 at an amount of about 0.2% to about 0.3% by mass of vasopressin.
 34. The method of claim 16, wherein the pharmaceutical composition further comprises a peptide of SEQ. ID. NO.: 10 at an amount of about 0.3% to about 0.4% by mass of vasopressin.
 35. The method of claim 16, wherein the pharmaceutical composition is at a pH of about 3.5.
 36. The method of claim 16, wherein the pharmaceutical composition is at a pH of about 3.6.
 37. The method of claim 16, wherein the pharmaceutically acceptable excipient in the pharmaceutical composition is acetic acid.
 38. The method of claim 16, wherein the pharmaceutically acceptable excipient in the pharmaceutical composition is acetate.
 39. The method of claim 16, wherein the pharmaceutically acceptable excipient in the pharmaceutical composition is a combination of acetic acid and acetate.
 40. The method of claim 16, wherein the subject has a hypotension associated with vasodilatory shock.
 41. The method of claim 40, wherein the vasodilatory shock is post-cardiotomy shock or septic shock.
 42. The method of claim 16, wherein the intravenous administration provides to the subject from about 0.01 units/minute to about 0.1 units/minute vasopressin, or a pharmaceutically acceptable salt thereof.
 43. The method of claim 42, wherein the intravenous administration further comprises titrating up by 0.005 units/minute vasopressin, or a pharmaceutically acceptable salt thereof, at 10- to 15-minute intervals before achieving a target blood pressure response.
 44. The method of claim 42, wherein the intravenous administration further comprises attaining a target blood pressure in the subject and continuing the administration for a period of about 8 hours.
 45. The method of claim 44, wherein the intravenous administration further comprises, after the period of about 8 hours, reducing the administration by about 0.005 units/minute vasopressin, or a pharmaceutically acceptable salt thereof. 